Until now, these were haphazardly enforce inline in blueprint
implementations. The only thing stopping complete breakage is that
`EndPlacement` wasn't called (too much) from outside the blueprint,
leaving them responsible for their own placement.
By moving this conditional out of the provided paramters to
`EndPlacement`, it allows more flexible usage of that method externally.
Coming in a future PR.
Timeline blueprint is glitched when the hit object has negative duration.
Negative duration is unwanted anyways so placement implementation is fixed instead of supporting it in timline blueprint.
